Power tools may use brushless AC motors that have one or more phases. A given power tool may be intended to rotate in a first direction but not intended to rotate in an opposite second direction. Where not intended, the rotation in the opposite second direction, or reverse rotation, may result in the power tool accessories loosening and thus becoming detached from the power tool during normal operation. Therefore, there is a need to detect reverse rotation of the motor in such a power tool and to stop power tool operation if the reverse rotation is detected.
Brushless AC motors used in power tools may be capable of higher rotation speeds than are acceptable to other components of the power tool, including the attached accessories. There is, therefore, a need to detect an overspeed condition and to shut down the power tool when the overspeed condition is detected.
This section provides background information related to the present disclosure which is not necessarily prior art.